JP3330202B2 - Urethane oligomer and active energy ray-curable urethane resin composition containing the oligomer as a curable component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel urethane oligomer and an active energy ray-curable urethane resin composition containing the oligomer as a curable component.

[Prior art]

[0002] Urethane acrylate oligomers have ultraviolet curing properties and are useful as coating forming materials such as paints, inks, protective coatings and adhesives, like epoxy acrylate oligomers and polyester acrylic oligomers.

For the sake of convenience in the following description and for intuitive understanding of the molecular structure, an active hydrogen-containing (meth) acrylate monomer unit may be replaced with “=” if necessary.
The polyisocyanate unit is represented by "O", the low molecular weight polyol is represented by "-", and the high molecular weight polyol is represented by "...".

Japanese Patent Application Laid-Open No. 57-17 / 1987 filed by the present applicant
No. 2915 discloses a molecular weight of 500 to 200 containing 1,4-cyclohexanedimethanol as a polyhydric alcohol.
A photocurable urethane acrylic resin composition using a prepolymer obtained by reacting a diisocyanate compound with a low molecular weight polyester resin of No. 0 and then reacting an active hydrogen-containing acrylic monomer is shown. The structure of the obtained prepolymer is as follows.

Japanese Patent Application Laid-Open No. 57-65 filed by the present applicant
No. 714 (Japanese Patent Publication No. 2-10166) discloses a polyester polyol having a molecular weight of about 1,000 to 5,000.
A photocurable resin composition using a prepolymer obtained by reacting (A) with a polyvalent isocyanate compound (B) and then reacting with an active hydrogen-containing acrylic monomer (C) is shown. In Example 1, 3 moles of (B) were reacted with 2 moles of (A), and then 2 moles of (C) were reacted.
The structure of the obtained prepolymer is as follows.

JP-A-3-244618 discloses a polyether glycol (a) and a diisocyanate compound.
(b) shows an ultraviolet-curable urethane compound obtained by reacting a dihydric alcohol (c) having a molecular weight of 300 or less with a vinyl unsaturated monomer (d) having a hydroxyl group. Here, the polyether-based glycol unit is a soft segment, and a hard segment of a continuous urethane bond composed of a dihydric alcohol and a diisocyanate is located at both ends. In other words, the structure of this prepolymer is as follows: = −-… ...…-○ = (4) = ○-○-○ ...…-○-○ = (5) = ○-○-○-○ ...…- ○ − ○ − ○ = (6)

Japanese Patent Application Laid-Open No. 4-77515 discloses a reaction obtained by reacting a polyol having a molecular weight of 1,000 to 10,000, a diisocyanate compound, a dihydric alcohol having a molecular weight of 300 or less, and a vinyl unsaturated monomer having a hydroxyl group. The resulting radiation-curable oligomer is shown. The structure of this oligomer is as follows: = ○-○ ...…-○ = (7) = ○-○ ... ○-○ ...−-… = (8) = ○-○ ... ○-○ ...…- ○ …… ○ − ○ = (9)

[0008]

SUMMARY OF THE INVENTION Among the above, Japanese Unexamined Patent Publication No.
According to the example, the photocurable urethane acrylic resin composition disclosed in JP-172915-B has a balance between tensile strength and elongation of 150 kg / cm ^{2 to} 310% and 200 kg / cm ^2.
-180%, 240 kg / cm ² -90%, 230 kg / cm ² -1
60% and 240 kg / cm ² -130%, and both strength and elongation tend to be insufficient. In addition, there is a problem that when the elongation is to be maximized, the strength is further reduced.

JP-A-57-65714 (Japanese Patent Publication No.
In the photocurable resin composition using the prepolymer disclosed in Japanese Patent Application Laid-Open No. 10166), an example in which 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate is further used in combination with the prepolymer as a monofunctional polymer. According to the above, the balance between tensile strength and elongation is 1
80 kg / cm ² -380%, 120 kg / cm ² -310%, 14
0 kg / cm ² -430%, 120 kg / cm ² -360%, 75 kg
/ cm ² -470% and satisfactory results can be obtained in terms of elongation, but there is a problem that the tensile strength is insufficient. When not using a monofunctional polymer together,
Tensile strength, Young's modulus and elongation tend to decrease significantly. Further, according to additional tests by the present inventors, the photocurable resin composition disclosed in the publication has a disadvantage that the tack-free time is 5 seconds or more, which is long for the photocurable resin composition.

According to the embodiment, the ultraviolet-curable urethane compound disclosed in JP-A-3-244618 has a tensile strength-elongation balance of 230 kg / cm ² -450%,
It is 250 kg / cm ² -440%, and although satisfactory results can be obtained in terms of elongation, there is a problem that the tensile strength is insufficient.

On the other hand, the radiation-curable oligomer disclosed in JP-A-4-77515 has a tensile strength-elongation balance of 450 kg / cm ² -80 according to the embodiment.
0%, 480 kg / cm ² -760%, 360 kg / cm ² -700
%, 470 kg / cm ² -550%, 440 kg / cm ² -620%
And both the tensile strength and the elongation are extremely excellent. However, the cured coating obtained from this oligomer has the disadvantage that the Young's modulus is as low as 15 to 55 kg / cm ² . According to additional tests by the present inventors, the cured film has insufficient abrasion resistance according to a Taber abrasion test, for example, 10 to 22 mg, and has insufficient stain resistance (drawn with a quick-drying oil-based ink. (When left at room temperature for 24 hours and wiped off with ethanol, a trace of the line is clearly left.) There is also a disadvantage that if dirt or dust adheres, it cannot be easily cleaned.

Under the above-mentioned circumstances, the present invention provides a novel material having excellent tensile strength and elongation, high Young's modulus, good abrasion resistance and stain resistance, and a short tack-free time during curing. It is an object of the present invention to provide a urethane-based oligomer and an active energy ray-curable urethane-based resin composition containing the same as a curable component.

[0013]

According to the urethane oligomer of the present invention, an active hydrogen-containing (meth) acrylate monomer unit is represented by "=", a polyisocyanate unit is represented by "O", and a low molecular weight polyol having a molecular weight of 300 or less is represented by "-". When a high molecular weight polyol having a molecular weight of 500 or more is represented by "...", it is represented by the following formula: = O-O ... O = (1).

The active energy ray-curable urethane resin composition of the present invention contains the above urethane oligomer as a curable component.

Hereinafter, the present invention will be described in detail.

The urethane oligomer of the present invention is represented by the above formula (1). Each component constituting the oligomer will be described in order.

Examples of active hydrogen-containing (meth) acrylate monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, tripropylene glycol (meth) acrylate, and 1,4-butylene glycol monoacrylate. (Meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate, glycerol mono (meth) acrylate, glycerol di (meth) acrylate, glycerol methacrylate acrylate, and the like are used.

As the polyisocyanate, for example,
2,4- or 2,6-tolylene diisocyanate, m
-Or p-xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane-4,4'-
Diisocyanate or a modified or polymerized product thereof, hexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, naphthalene diisocyanate, and the like are used.

The low molecular weight polyol having a molecular weight of 300 or less includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2- or 1,3-propylene glycol, 1,3- or 1,4.
-Butanediol, 1,5-pentanediol, 1,6
-Hexanediol, neopentyl glycol and the like are used.

Examples of the high molecular weight polyol having a molecular weight of 500 or more include polyether polyols, polyester polyols, polycarbonate polyols, acrylic polyols, polybutadiene polyols, and polyolefin polyols having a molecular weight of 500 or more, especially 500 When the molecular weight is less than 500, the elongation of the cured product becomes insufficient.

The urethane oligomer of the present invention is typically prepared by mixing 2 mol of polyisocyanate and 1 mol of low molecular weight polyol in an inert gas atmosphere such as nitrogen gas at a temperature of 50 to 95 ° C. in the presence of a suitable solvent. And then react by adding 1 mol of high molecular weight polyol,
Further, a method is employed in which 1 mol of a polyisocyanate is added and reacted, and finally 2 mol of an active hydrogen-containing (meth) acrylate monomer is added and reacted at a temperature of about 50 to 80 ° C. At the time of the reaction, a catalyst can be appropriately present. However, the reaction molar ratio of each component described above shows a typical case.

In addition to the above-mentioned method, 3 mol of polyisocyanate and low molecular weight polyol 1
Reacting with 1 mol of a high molecular weight polyol, and then reacting by adding 2 mol of a (meth) acrylate monomer containing an active hydrogen, and 3 mol of a polyisocyanate and a high molecular weight polyol 1
Reacting with 1 mol of a low molecular weight polyol and 2 mol of an active hydrogen-containing (meth) acrylate monomer, and then reacting with 2 mol of a polyisocyanate and an active hydrogen-containing (meth).
A method of reacting 2 mol of an acrylate monomer, then reacting 1 mol of a high molecular weight polyol, and further reacting by adding 1 mol of a polyisocyanate and 1 mol of a low molecular weight polyol is used.

The total molar ratio of each component is based on 3 mol of polyisocyanate, 1 mol of low molecular weight polyol, 1 mol of high molecular weight polyol and 2 mol of active hydrogen-containing (meth) acrylate monomer. Fluctuations of about 3.5 moles, 0.5 to 1.5 moles of low molecular weight polyol, 0.5 to 1.5 moles of high molecular weight polyol, and 1.5 to 2.5 moles of active hydrogen-containing (meth) acrylate monomer are permissible.

Thus, a urethane oligomer represented by the following formula is obtained. However, in the following formula, as described above, the active hydrogen-containing (meth) acrylate monomer unit is “=”, the polyisocyanate unit is “「 ”, and the low molecular weight polyol having a molecular weight of 300 or less is“ − ”. , A high molecular weight polyol having a molecular weight of 500 or more
… ”. ＝ ○ － ○ …… ○ ＝ (1)

The active energy ray-curable urethane resin composition of the present invention contains the above urethane oligomer as a curable component.

When the composition is cured by irradiation with an electron beam, a photopolymerization initiator is not usually used, but when the composition is cured by irradiation with ultraviolet rays, a photopolymerization initiator is blended. Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin phenyl ether, benzyl diphenyl disulfide, azobisisobutyronitrile, Dibenzyl, diacetyl, anthraquinone, naphthoquinone, benzophenone, pivaloin ethyl ether, benzoyl peroxide, benzyl ketal, 1,1-dichloroacetophenone, para-t-butyldichloroacetophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,2-diethoxyacetophenone, 2,2-
Dimethoxy-2-phenylacetophenone, 2,2-dichloro-4-phenoxyacetophenone, Michler's ketone, phenylglyoxylate, α-hydroxyisobutylphenone, dibezosparone, benzophenoneamine, 1- (4-isopropylphenyl) -2-hydroxy- 2-Methylpropanone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone and the like are used, and the compounding amount may be about 1 to 10% by weight based on the whole composition. Many.

Various other additives can be added to the composition. Examples of additives include fillers, dyes and pigments, oils, plasticizers, waxes, desiccants, dispersants, wetting agents, emulsifiers, gelling agents, stabilizers, defoamers, leveling agents, and thixotropic agents. Is raised.

The composition also contains styrene, vinyltoluene, α-methylstyrene, methyl methacrylate,
Methyl acrylate, ethyl acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, cyclohexyl acrylate, dicyclopentadiene acrylate, N-vinylpyrrolidone, furfuryl acrylate, carbitol acrylate, benzyl acrylate, butoxyethyl acrylate , Allyl acrylate, phenoxyethyl acrylate, acryloxyethyl phosphate, 2-vinylpyridine, and other various monomers can be blended in desired amounts.

After the composition is applied to an object, the composition is cured by irradiating it with ultraviolet rays or an electron beam. As a light source for performing ultraviolet irradiation, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, and the like are used. The irradiation time varies depending on the type of light source, the distance between the light source and the coated surface, and other conditions, but at most a few tens of seconds is sufficient, and may be a few seconds, and sometimes a fraction of a second in some cases. After the ultraviolet irradiation, heating can be performed as necessary to complete the curing. In the case of electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 KeV is preferably used, and the irradiation amount is preferably 2 to 5 Mrad.

The urethane acrylate oligomer and the active energy ray-curable resin composition containing the oligomer according to the present invention can be used as paints, inks, protective coatings,
It is useful as various film forming materials such as an anchor coating agent, a magnetic powder coating binder, a sand blast coating, an adhesive, and a printing plate.

[0031]

Since the urethane oligomer of the present invention has a unique molecular structure, a film obtained from an active energy ray-curable urethane resin composition containing the oligomer as a curable component has a tensile strength, elongation, Both have high Young's modulus and good abrasion resistance and stain resistance. Another advantage is that the tack-free time during curing is short.

[0032]

The present invention will be further described with reference to the following examples. Hereinafter, “parts” and “%” are shown on a weight basis.

Example 1 <Urethane oligomer> 290.3 g (1.66 mol) of tolylene diisocyanate was placed in a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser and a nitrogen gas inlet.
Neopentyl glycol 57.9 g (0.55 mol), toluene
274.8 g was charged and reacted at an internal temperature of 80 to 90 ° C. for 5 hours. When the remaining isocyanate groups became 15%, 347.3 g of polytetramethylene glycol having a molecular weight of 650 (0.
53 mol) and 0.15 g of dibutyltin dilaurate were added and reacted for another 5 hours. 5% residual isocyanate groups
Was maintained at 60 to 70 ° C., and 129.0 g (1.11 mol) of 2-hydroxyethyl acrylate was added and reacted for 4 hours. When the remaining isocyanate group became 0.5%, the reaction was stopped.

FIG. 1 shows an NMR chart of the obtained urethane oligomer, and FIG. 2 shows an IR chart thereof. The urethane-based oligomer has the following structure: ○-○... ＝= (1)

<Active energy ray-curable urethane resin composition> The composition containing the urethane oligomer obtained above (resin content: 100 parts) was added to a 1-hydroxycyclohexyl phenyl ketone (a product of Ciba Geigy) as a photoinitiator. 5 parts of Irgacure 184) were added and mixed to prepare an ultraviolet-curable resin liquid. This resin solution is coated on a polyester film to a thickness of 100 μm using an applicator, dried with hot air at a temperature of 75 ° C. for 10 minutes, and then conveyed from a height of 20 cm to a conveyor of 5 m / min using a high-pressure mercury lamp 80 W / cm. One-pass ultraviolet irradiation was performed at a speed to form a cured film. The tack-free time was as short as 0.5 seconds.

The formed film was peeled from the polyester film to prepare a test piece having a width of 10 mm and a length of 25 mm, and the tensile strength, Young's modulus and elongation were measured by an autograph under the conditions of a tensile speed of 20 mm / min. . The results are shown below. Tensile strength 382 kg / cm ² Young's modulus 153 kg / cm ² Elongation 363%

The coating was measured for wear using a Taber abrasion tester and tested for stain resistance. The results are shown below. Regarding the stain resistance, draw a commercially available red and black quick-drying oil-based ink on the film,
After standing at room temperature for 24 hours, it was wiped off with ethanol, and the case where there was no trace was evaluated as 跡, the case where the trace was slightly left was evaluated as Δ, and the case where the trace was clearly observed was evaluated as ×. Wear resistance 0.6 mg (load 1000g, wheel CS-10, rotation speed 500
rpm) Stain resistance Black quick-drying oily ink ○ Red quick-drying oily ink ○

Examples 2 to 3 A urethane oligomer was produced in the same manner as in Example 1 except that the following components were used, and a cured film was formed by irradiation with ultraviolet rays.

[0039] Example 2 - Charge components and total molar ratio of isophorone diisocyanate 3 mole of neopentyl glycol 1 mol molecular weight 650 polytetramethylene glycol 1 mol of 2-hydroxyethyl acrylate 2 moles and measurement results of tensile strength 360 kg / cm ² Young Rate 124 kg / cm ² elongation 420% abrasion resistance 1.4 mg (load 1000g, wheel CS-10, rotation speed 500
rpm) Stain resistance Black quick-drying oily ink ○ Red quick-drying oily ink ○

Example 3 Charged Components and Total Charged Molar Ratio Xylylenediisocyanate 3 moles Neopentyl glycol 1 mole Polytetramethylene glycol having a molecular weight of 650 1 mole 2-hydroxyethyl acrylate 2 moles Measurement result Tensile strength 343 kg / cm ² Young's modulus 118 kg / cm ² Elongation 382% Wear resistance 1.7 mg (1000 g load, wheel CS-10, rotation speed 500)
rpm) Stain resistance Black quick-drying oily ink ○ Red quick-drying oily ink ○

Comparative Example 1 Adipic acid was placed in a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet under a nitrogen stream.
1.0 mole, 0.56 mole of ethylene glycol and 1,4-
0.56 mol of butanediol is charged and stirred at a temperature of 2
The mixture was heated at 30 ° C. for 17 hours. When the acid value reached 0.6 KOH mg / g, the reaction was stopped and the mixture was cooled. Hydroxyl value is 55.6 KOHmg / g
Met. The number average molecular weight of this polyester polyol was 2,080 as measured by high performance liquid chromatography.

To 2 moles of this polyester polyol, 3 moles of a mixture of 2,6-tolylene diisocyanate and 2,4-tolylene diisocyanate at a weight ratio of 20% / 80% were mixed, and an appropriate amount of ethyl acetate was further added. After the addition, the mixture was reacted at a temperature of 60 to 90 ° C., and when the remaining isocyanate groups became 1.8%, 2.06 mol of 2-hydroxyethyl acrylate and monomethyl ether hydroquinone were added.
0.04% was added and the mixture was reacted at 50 ° C. for 11 hours. When the residual isocyanate group became 0.2%, the reaction was stopped. The hydroxyl value was 3.3 KOHmg / g.

The obtained urethane-based oligomer has the following structure: ## EQU1 ##

To 100 parts of the urethane oligomer obtained above, 3 parts of benzoin isopropyl ether was added to form a uniform resin solution. This resin solution was applied on a polyester film to a thickness of 100 μm using an applicator.
After drying with hot air at 5 ° C for 10 minutes, a high-pressure mercury lamp 80
One pass of ultraviolet irradiation was performed at a conveyor speed of 5 m / min from a height of 20 cm using W / cm to form a cured film.

Thereafter, test pieces were prepared in the same manner as in Example 1, and tensile strength, Young's modulus and elongation were measured. The results are shown below. Tensile strength 75 kg / cm ² Young's modulus 40 kg / cm ² Elongation 120%

[0046]

Since the urethane oligomer of the present invention has a unique molecular structure, the coating obtained from the active energy ray-curable urethane resin composition containing the oligomer as a curable component has a tensile strength and an elongation. Both the degree and Young's modulus are large, and the abrasion resistance and stain resistance are also good. Another advantage is that the tack-free time during curing is short.

[Brief description of the drawings]

FIG. 1 shows the N of the urethane oligomer obtained in Example 1.
It is an MR chart.

FIG. 2 shows I of the urethane oligomer obtained in Example 1.
It is an R chart.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C08F 290/06

Claims (2)

(57) [Claims] (1) An active hydrogen-containing (meth) acrylate monomer unit is represented by “=”, a polyisocyanate unit is represented by “、”,
When the low molecular weight polyol having a molecular weight of 300 or less is represented by "-" and the high molecular weight polyol having a molecular weight of 500 or more is represented by "...", a urethane oligomer represented by the following formula: 2. An active energy ray-curable urethane resin composition containing the urethane oligomer according to claim 1 as a curable component.